Preheat the oven to 350°F (175°C) and line a cupcake pan with your favorite liners.

In a large bowl, whisk together flour, cocoa powder, sugar, baking powder, baking soda, and salt until evenly mixed.

Crack in the eggs, pour in the milk, oil, and vanilla extract. Mix until everything is well combined and smooth—about 2-3 minutes.

Gradually stir in the boiling water, taking care to bring the batter together. The consistency should be very smooth and liquid-like.

Scoop the batter into the prepared liners, filling each about 2/3 full.

Bake for 18-20 minutes. Check for doneness by inserting a toothpick; it should come out clean.

Once baked, let the cupcakes cool in the pan for about 10 minutes, then transfer them to a wire rack to cool completely.

In a mixing bowl, beat softened butter until creamy. Gradually add powdered sugar and mix until smooth and fluffy.

Use a pastry bag to pipe the buttercream onto the cooled cupcakes in your desired pattern.

Heat heavy cream in a saucepan until just simmering. Pour it over the chopped chocolate in a bowl, stirring until completely smooth.

Pour the ganache over the frosted cupcakes, allowing it to cascade down the sides for a gourmet look. Allow to set before serving.